There doesn't even seem to be a professional course in gunsmithing in this country.

People either learn in the Army Ordnance Corps, get a job in a gunshop and pick it up as they go along, or come to it from things like tool making etc.

Those people with a mechanical engineering background who know how to use lathes etc, are half way there.

Becoming an airsoft tech shouldn't take too long if you have the aptitude and know how to use a dremel and soldering iron.

I imagine you have to find a good airsoft tech and start by watching him work and helping him out with the simpler things. I doubt you would be paid for it. But if I were keen to become a tech I wouldn't mind putting in some time in the evenings and at the weekends for free.

I've learned everything I know from watching, talking to and helping out my dad as he worked it out as he went. We both got into it at the same time and both have an interest and understanding of engineering along with my dad's career in various engineering jobs. Best way to learn a skill like this is to watch, help and learn from someone who really knows what they're doing, multiple if possible as everyone has their preferred methods, techniques and parts and the wider variety of skills you learn the better you will be. If there was a course in it there is only so far it could take you. You can get taught what to do and how to do it but unless youre learning why you're doing it and given the chance to make mistakes there's only so good you can get.

It takes experience, start with working on your own stuff and build from there.

Most jobs arent too bad, the basic principles of the guns are the same and fundamental skills like soldering, drilling and tapping properly, the basic principles of fault finding etc are mostly universal.

To quote my grandfather you need to know 2 things to fix something- what it's meant to do and how its meant to do it.

I generally do all my own tech work, the only time i go to the shop is when its something that might need their resources, for example when sorting the ascu2 cutoff lever we literally ended up fishing through a box of assorted cutoff levers to find the 1 lever that had the correct throw for the switch. Fortunately our relationship is pretty decent insofar as they'll let me just tear away.

Youtube videos can be great for sanity checking, for example if somethings a bit stiff and youre not sure if you should just force it or if there's some sneaky hidden pin/screw that you dont know is there.

The other thing that helps is getting the proper tools for the job, for example you can use a screwdriver as a ghetto punch but in the long term the proper tool will make the job easier and less damaging, or you can use a standard alan key set with ball ends but proper hex drivers are an absolute dream by comparison and are less likely to round, same applies to keeping stock of spare screws that you can dig through and find a proper replacement.

Also remember if you're resorting to ptfe tape on a component that didnt originally come with it on you've already lost (this has nothing to do with the amount of unnessecary ptfe tape i pulled out of a mates gun when i was working on it, nothing at all )

The only other thing is an attitude of doing things right, as a friend of mine says "you say you dont have time to do it right but you have time to do it twice", sure it might mean your pew is out of action while waiting for a part but that just means you dont have enough backups....